By Kim Hyun SEOUL, Aug. 12 (Yonhap) -- Kim Jee-woon's new thriller, "I Saw the Devil," which hit theaters on Thursday, almost didn't make it to the big screen. Due to its hardcore violence, the film initially received a restricted screening rating. Filmmakers had to trim some of the more excruciating fat before the 18-rated thriller could be shown in theaters.

Kim called watching the finished product, which is a grueling exploration into the showdown between a serial killer and an equally brutal avenger, "eating sushi short of wasabi" at a press premier Wednesday. Despite Kim's comments, the drama is overladen with a series of decapitations and gripping violence. Yet, many of them are no more cannibalistic than what we have seen in thrillers like Park Chan-wook's "Sympathy for Lady Vengeance" or Ridley Scott's "Hannibal."File photo However, what really counts here is the matter of effectiveness. Does the drama pack enough empathy for the audience to sit through the violence?

The movie opens on a beautiful snowy night as romantic guitar melodies flow to the methodical movements of a car's windshield wipers. Ju-yeon (Oh San-ha), the daughter of a retired police officer and fiancee of a top secret agent, gets a flat outside town and has to wait for assistance. It's here that the serial killer, Gyeong-cheol (Choi Min-sik), makes his entrance, appearing from out of nowhere.

Gyeong-cheol is a stony-eyed psychopath who kills for amusement. A plump, middle-aged, school bus driver in a Seoul suburb, he lets no chance go to waste. Ju-yeon becomes his latest prey and is found decapitated in a horrible state.

Su-hyeon (Lee Byung-hun), the victim's fiance and a secret guard with the National Intelligence Service, decides to track down the perpetrator. He's bent on making Gyeong-cheol suffer as horribly his fiance did.

After planting a GPS chip on the villain, Su-hyeon is able to effectively track the serial killer, but when he lashes out, his attacks fail to deal the finishing blow.

Vexed with entrapment, Gyeong-cheol seeks help from his fellow serial killer and discovers the GPS capsule. This is when the real showdown begins.

To endure the tormenting scenes of violence, the audience needs to form an emotional bond with Su-hyeon. They need to identify with his quest for vengeance, and the reasons why he keeps catching and setting the serial killer free. Su-hyeon apparently does this to make him suffer, but the motive works against the moral element of the drama. The empathy aspect suffers as a result.

Befitting his reputation from "The Good, the Bad, the Weird" and "A Bittersweet Life," Kim has beautifully shot his latest noir. Each scene is masterfully drawn from real-world Seoul and its idyllic suburbs.

But the central part of the film lies with the frenetic confrontation between the two actors. Choi has a marvelously impassive face when he says, "I don't know pain, nor fear. There's nothing you can get from me. You've already lost." His emotionless face never wavers.

It is Lee who has to express the subtle changes of a man whose quest drains him over time. To endure the 144-minute revenge drama, the audience needs to identify with Lee's gripping anger and his excruciating method of vengeance. Choi, who played a flesh-eating perpetrator in "Sympathy for Lady Vengeance" (2005), said he focused on "technically" playing his role.

"I only had a few scenes as the criminal in 'Lady Vengeance' and I was thirsty. With 'I Saw the Devil,' it's excessive," he said in the press screening. "This is perhaps the film where I was the least immersed among the films I've done, and I approached it rather technically."

Lee, who made his Hollywood debut with "G.I. Joe: The Rise of Cobra" last year, recalled his role as "extremely exhaustive." It was "challenging to play a man who has to avenge with no facial expressions, but at the same time who has to subtly show various emotions of anger, sadness and anxiety."

"I Saw the Devil," produced by Peppermint and Co. and distributed by Showbox, was released on Thursday.